Question: Whar kind of doctor should I see for pain in joints and unusual amount of clicking and popping sounds from joints?

The pain is in my back, hip and now fingers. Not all fingers, just a couple. Feels like I bent them wrong way and they are trying to heal but I didnt. They only hurt when I bend them or try to use them. Hurt in morning, sometimes start to feel a little better, then start aching again, this goes on all day and night.
I recently had mri and nerve test to check for sciatic nerve pain regarding my back and leg pain. Mri showed three bulging disks. I dont know if this is related to pain I have when standing up when on floor and walking though. My neurologist did the tests.
When I walk I have loud popping sound and feeling in my hip area, also alot of popping and cracking in fingers, wrist, ankles. I know I have osteopenia and not sure if that comes into play into all of this. I have stiffness but not noticing swelling. The back and leg/hip pain started in Feb 2014, the popping sound about a month ago. The other popping sounds and pain in fingers started about a month ago as well.
I just dont want things to get worse and not sure if this is something that will if I ignore it. My neuroligist is sending me to pain managment specialist for shots in my back but the appt is not even set up as of yet and I dont know if they can help with this other stuff cause I dont know if its related. Thank you for your time.